Cancer is the first leading cause of death and the liver cancer is the most lethal cancer along the years in Taiwan. The main cause of cancer is due to cell abnormal transformation or abnormal proliferation, wherein, a solid lesion formed by an abnormal growth of cells (termed neoplastic) which looks like a swelling is so called tumor. The tumor is classified as solid tumor and non-solid tumor. The solid tumor includes hepatic cancer, non-small cell lung cancer (NSCLC), colon cancer, melanoma, ovary cancer, prostate cancer, kidney cancer, breast cancer, gastric cancer, etc. Most of the non-solid tumors are hematologic malignancies which include leukemia, malignant lymphoma, etc. Recently, the rate of suffering from hepatic cancer and colon cancer is getting higher and higher. How to treat these cancers becomes a serious issue.
The research of aging has become a general focus in the whole world, and it is found that aging is associated with elevated oxidative stress and increased cancer risk. Cancer occurrence is positively correlated with the process of aging. Cancer and aging share some common mechanisms for their biological functions.
Pentose phosphate pathway (PPP) is an important cellular defense system against oxidative stress by removing excessive Reactive Oxygen Species (ROS) from mitochondrial oxidative phosphorylation. The major function of PPP is to generate NADPH to provide more reduced forms of glutathione counteracting the damaging effects of ROS.
Most cancers were found with increased activities of pentose phosphate pathway. Ribose-5-phosphate isomerase (RPI) is an enzyme involved in pentose phosphate pathway (PPP) to convert the ribulose-5-phosphate into ribose-5-phosphate wherein the ribose-5-phosphate is an important source of synthesis DNA and RNA in cells. Many researches show that RPI is involved in the aging pathway and the anti-oxidant pathway. However, there is no research shows that RPI can be used as an important index for cancer detection.